Cargo containers are commonly used by travelers to transport additional cargo such as luggage and the like which cannot fit inside an automobile. Such cargo containers are attached to a rack which is mounted on the roof of the vehicle. However, since the cargo containers are available in various sizes, the racks must be adjustable or replaceable to accommodate different-sized cargo containers. A cargo trailer is needed which is capable of being towed by a motorcycle and can be adjusted to accommodate cargo containers of various sizes.